The field of this invention relates separators in a closed crankcase ventilation system.
Government regulations relating to environmental concerns have mandated that many engines have a closed crankcase ventilation system. Commonly, these closed systems re-circulate any blow-by gases escaping from the combustion chambers and passing into the crankcase back into the air intake system. These blow-by gases, which are loaded with unburned gaseous hydrocarbons, are then re-circulated back to the intake manifold to be burned upon the next pass into the engine.
However, the crankcase gases are also usually loaded with oil particulates. Under extreme conditions, excess oil passing through the intake system may cause harm to the engine and cause more pollutants than what was being eliminated by the re-circulation of the blow-by gases. Thus, oil needs to be separated out before the gases are reintroduced into the air intake system of the engine and re-burned.
One present in-line closed re-circulation system is disclosed in U.S. Pat. No. 4,724,807 which has an in-line separator made with conduits with arcuate channel walls forming a convoluted arcuate pathway for the exhaust gas/oil mixture. The separator is interposed between the clean air intake filter and the turbo-compressor air inlet system. The position of this separator requires that the separator have a moderately small size to fit between the air filter and turbo intake and requires that it be downstream from the crankcase depression regulator. These factors limit the capacity and effectiveness of the separator returning oil against a substantial differential pressure to the positively pressured crankcase.
What is needed is an expeditiously constructed separator system that has enough capacity to prevent oil from entering the air intake in a cylinder kit failure situation and eliminates the resistance of draining oil back into a positively pressurized crankcase.
In addition, there is a need for a separator system that protects the engine against a sudden increase in oil discharge due to operating conditions, including extreme tilt of the engine during operation.
In accordance with one aspect of the invention, a closed crankcase re-circulation system for an internal combustion engine includes an exhaust gas-oil separator operably interposed between an engine breather and a crankcase depression regulator. The exhaust gas-oil separator has an inlet in communication with an outlet of an engine breather for communication with the internal space of the crankcase. Commonly, the engine breather may be mounted in the rocker arm cover with the engine block and cylinder heads having passages to the crankcase.
A gas outlet is in communication with a line leading to an air intake system of the engine. The gas outlet is positioned at a high portion of the separator. The line has a crankcase depression regulator mounted downstream from the separator. An oil drain outlet is in communication with the crankcase for draining oil back thereto.
Preferably the separator is longitudinally extending from the inlet to the outlet and drain. The oil drain outlet is at a lower portion of the separator. Baffles are interposed between the inlet and the gas and oil drain outlets. Preferably the baffles transversely and alternately extend from opposite sides of the separator to form a convoluted passage for the blow by gasses as they pass from the inlet to the gas outlet.
The separator desirably has a floor surface canted downwardly from the inlet to the oil drain outlet with the oil drain outlet located at a low portion of the canted floor surface to provide for flow of the separated oil to the oil drain outlet.
In one embodiment the separator has a generally frusto-conical shape extending from the inlet to the gas outlet and oil drain outlet. In this embodiment, it is preferable that each baffle has an oil drain passage located at a low lateral point at the floor surface to provide for downward flow of the oil through the baffle and toward the drain. It is also preferable that a filter media is interposed between an end wall in proximity to the gas outlet and a last downstream baffle. The filter media is operable interposed between the gas outlet and the oil drain outlet.
In another embodiment, the separator has a generally rectangular shape in plan view with vertical sidewalls and vertical end walls. The floor surface is generally flat in the lateral direction. The baffles alternately extend from the vertical sidewalls. It is desirable in this embodiment that the inlet is positioned at an upper section of one end wall adjacent a higher end of the floor surface. The gas outlet is positioned at an upper section of an opposite end wall adjacent to the lower end of the floor surface. The oil drain outlet is positioned at a lower section of the opposite end wall.
In accordance with another aspect of the invention, a separator for a closed crankcase ventilating system includes a generally longitudinally and horizontally extending body with an inlet at an upstream end and a gas outlet and oil drain outlet at a downstream end. The separator has a floor surface canted downwardly from the upstream end to the downstream end. The oil drain outlet is located at a low portion of the canted floor surface. A plurality of baffles transversely extend laterally within the body and are alternately to opposite sides of the body.
Preferably, the separator body has a generally frusto-conical shape extending from the inlet to the gas outlet and oil drain outlet. Preferably, each baffle has an oil passage located at a low lateral point at the floor surface to provide for downward flow of the oil through the baffle and toward the oil drain outlet.
In this fashion, a separator has the efficiency and capacity to adequately separate sufficient oil form the crankcase gases in a situation where a cylinder kit fails which significant blow by of oil and blow by gasses pass into the crankcase. In this way, the air intake system and turbo charge system are more adequately protected when a cylinder kit failure occurs.